Method for manufacturing a compostable plate

ABSTRACT

A method for manufacturing a compostable plate which comprises:
         a step of manufacturing a supporting layer made of compostable cardboard;   a step of printing at least one portion to be printed of the supporting layer made of compostable cardboard in order to obtain at least one respective printed portion, the step of printing being carried out using compostable inks;   a step of spreading, at least over the surface that defines the at least one printed portion, a compostable biopolymer in order to provide a protective layer;   a step of forming in order to provide a compostable plate, the step of forming comprising a thermoforming by insertion, between a male mold part and a female mold part, of the supporting layer which has the printed portion or portions and the protective layer.

The present invention relates to a method for manufacturing acompostable plate.

Nowadays disposable compostable plates are known, which are made ofcellulose pulp obtained for the most part from sugar cane.

The main limitation of the above mentioned disposable compostable platesconsists in the impossibility of carrying out printed designs, forexample for personalization.

It is furthermore important to emphasize that sometimes the term‘compostable’ is considered a synonym of the term ‘biodegradable’.

On the contrary, there is a substantial difference between the terms‘compostable’ and ‘biodegradable’.

A biodegradable element is not in fact automatically also compostable.

A material is defined as biodegradable if it can be broken down, bybacteria, sunlight and other natural physical agents, into simplechemical compounds like water, carbon dioxide and methane. This processapplies to a great many materials, but each element has its owndegradation time, which may be long. European regulations draw clearlines, however. In order to be considered biodegradable, a product mustbe broken down by 90% within 6 months.

In order to be considered compostable (convertible to compost, a naturalfertilizer) the material not only must be biodegradable but also must bedecomposable, and the decomposition process must occur in less than 3months.

The aim of the present invention is to make available a method formanufacturing a compostable plate which is capable of improving theknown art in one or more of the above mentioned aspects.

Within this aim, an object of the invention is to make available acompostable plate that can easily be printed.

Another object of the invention is to make it possible to personalizecompostable plates.

Another object of the invention is to provide a compostable plate and amethod for manufacturing a compostable plate that are highly reliable,easy to implement and low cost.

This aim and these and other objects which will become better apparenthereinafter are achieved by a method for manufacturing a compostableplate according to claim 1, optionally provided with one or more of thecharacteristics of the dependent claims.

Further characteristics and advantages of the invention will becomebetter apparent from the description of some preferred, but notexclusive, embodiments of the compostable plate and of the method formanufacturing a compostable plate according to the invention, which areillustrated for the purposes of non-limiting example in the accompanyingdrawings wherein:

FIG. 1 is a cutaway perspective view of a supporting layer associatedwith a printed design and covered by a protective layer;

FIG. 2 is a view similar to FIG. 1;

FIG. 3 is a perspective view of the cardboard of the supporting layerassociated with a printed design and covered by a protective layer aftercutting or die-punching;

FIG. 4 is a perspective view of a plate;

FIGS. 5 to 7 are views that are similar, respectively, to those in FIGS.2 to 4, of a variation of embodiment of the printed design.

With reference to the figures, the compostable plate, generallydesignated by the reference numeral 1, comprises a supporting layer 2made of compostable cardboard which has at least one printed portion 3which is printed with compostable ink.

The plate further has at least one protective layer 5, which is arrangedat least above the surface that defines each printed portion 3.

In particular, the protective layer 5 comprises a compostablebiopolymer.

The protective layer 5 is arranged at the surface that is intended toprovide the concave part of the compostable plate 1.

Advantageously, the compostable biopolymer comprises a film with athickness comprised between 12 μm and 30 μm, and preferably between 19μm and 23.8 μm.

Such film can be obtained by way of extrusion or spreading of thebiopolymer on the supporting layer 2, at the surface that defines theprinted portion 3 or the printed portions 3.

Conveniently, the compostable biopolymer has a melting temperature ofmore than 135° C.

The product commercially designated with the wording MATER-BI CX01A madeby Novamont SpA, Italy has been found to be particularly adapted to thepurpose.

Conveniently, the supporting layer 2 made of compostable paper comprisessubstantially cellulose paste.

With regard to the compostable inks, an ink commercially designated withthe wording Hidromat-B 463 made by La Sorgente S.P.A., Italy has beenfound to be particularly adapted to the purpose.

According to a further aspect, the present invention relates to a methodfor manufacturing a compostable plate 1.

The method comprises:

-   -   a step of manufacturing a supporting layer 2 made of compostable        cardboard;    -   a step of printing at least one portion to be printed of the        supporting layer 2 made of compostable cardboard in order to        obtain at least one respective printed portion 3, the step of        printing being carried out using compostable inks;    -   a step of spreading, at least at the surface that defines the        printed portion or portions 3, a compostable biopolymer in order        to provide a protective layer 5;    -   a step of forming in order to provide a compostable plate.

To provide the protective layer, it has been found to be particularlyadapted to use the product commercially designated with the wordingMATER-BI CX01A made by Novamont SpA, Italy.

Preferably, the compostable biopolymer used to provide the protectivelayer 5 is mixed, prior to the step of spreading, with a master batch ofgranules.

In particular, such master batch is adapted to fluidify the biopolymerand therefore to facilitate the step of spreading.

It has been found to be particularly efficacious to use a compostableink that is free from amines.

In this regard, it has been found to be particularly suitable to use aproduct commercially designated with the wording Hidromat-B 463 made byLa Sorgente S.P.A., Italy.

The step of forming comprises a thermoforming.

Specifically, the thermoforming is carried out by insertion, between amale mold part and a female mold part, of the supporting layer 2 whichhas the printed portion or portions 3 and the protective layer 5.

The thermoforming is performed at a temperature comprised between 60° C.and 75° C. as regards the male mold part and between 120° C. and 130° C.as regards the female mold part.

The male mold part has a coupling surface which is designed to pressagainst the protective layer 5.

The coupling surface of the male mold part has a plastic coating that isadapted to limit the temperature of the coupling surface.

Preferably, such plastic coating comprises a layer of Teflon.

In practice it has been found that the invention fully achieves theintended aim and objects by providing a method for manufacturingcompostable plates that is extremely reliable and capable of ensuring ahigh ratio of quality to production cost.

The present invention makes it possible to provide a completelycompostable plate provided by way of a thermoforming process.

By virtue of identifying the compostable biopolymer intended to providethe protective layer 5, a solution has been obtained that makes itpossible, notwithstanding the pressures and temperatures ofthermoforming, to obtain a plate that is completely compostable andprinted.

Furthermore, with the same performance, a product has been obtained thatis lighter and less voluminous, as well as printed, decorated orpersonalized.

The possibility for personalization is very important for largecompanies which thus can highlight their respect for the environment byusing compostable products with their brand and therefore preferringthem to plates made from recycled cardboard.

The invention, thus conceived, is susceptible of numerous modificationsand variations, all of which are within the scope of the appendedclaims. Moreover, all the details may be substituted by other,technically equivalent elements.

In practice the materials employed, provided they are compatible withthe specific use, and the contingent dimensions and shapes, may be anyaccording to requirements and to the state of the art.

The disclosures in Italian Patent Application No. 102017000059261 fromwhich this application claims priority are incorporated herein byreference.

1-6. (canceled)
 7. A method for manufacturing a compostable plate whichcomprises: a step of manufacturing a supporting layer made ofcompostable cardboard; a step of printing at least one portion to beprinted of said supporting layer made of compostable cardboard in orderto obtain at least one respective printed portion, said step of printingbeing carried out using compostable inks; a step of spreading, at leastover the surface that defines said at least one printed portion, acompostable biopolymer in order to provide a protective layer; a step offorming in order to provide a compostable plate, said step of formingcomprising a thermoforming by insertion, between a male mold part and afemale mold part, of said supporting layer which has the printed portionor portions and the protective layer.
 8. The method according to claim7, wherein said thermoforming is performed at a temperature comprisedbetween 60° C. and 75° C. as regards the male mold part and between 120°C. and 130° C. as regards the female mold part.
 9. The method accordingto claim 7, wherein said male mold part has a coupling surface which isdesigned to press against the protective layer, said coupling surface ofthe male mold part having a plastic coating that is adapted to limit atemperature of said coupling surface.
 10. The method according to claim9, wherein said plastic coating comprises a layer of Teflon.
 11. Themethod according to claim 7, wherein said compostable biopolymer used toprovide said protective layer is mixed, prior to the step of spreading,with a master batch of granules which is adapted to fluidify thebiopolymer and to facilitate the step of spreading.
 12. The methodaccording to claim 7, wherein said step of printing is carried out usinga compostable ink that is free from amines.